Part 3: Where does your water come from?

Listen below as Madeleine Brand and Saul Gonzalez report on the Los Angeles Aqueduct.

Los Angeles Department of Water and Power engineer Fred Barker knows where your water comes from. Holding a glass of tap water, he explains that it came through the plumbing of the downtown DWP building, through a water main that connects to the Salono Reservoir, which is out by Dodger Stadium. It’s called Solano Reservoir, so we have about a quart or half a quart of water here.

It’s plain old City of Los Angeles tap water. And it’s a blend of all the places, far and wide, that people in the city of Los Angeles now get their water.

Although the exact percentages can change dramatically from one year to the next, generally L.A. gets about half of its water from Northern California and the Colorado River, 10 percent from local groundwater sources, and a third from the Owens Valley.

After its long journey from the Owens Valley, water flows into the city in Sylmar near where the 405 and 5 freeways meet. After filtration, it’s then stored at the L.A. Reservoir, just across the 5 freeway from the cascades, before heading on to L.A. homes and businesses.

After it’s filtered, the water flows from here through the DWP’s massive network of 7,200 miles of pipes, 88 pumping stations and more than one hundred storage tanks and reservoirs.

Except for five out of 23, we don’t use L.A.’s open reservoirs for drinking water any more. Federal regulators found that when sunlight hit the chemically treated water – it became unsafe to drink. So those scenic places, like the Hollywood Reservoir, Stone Canyon, and the Encino Reservoir have been taken out of direct service. But they are kept in case of emergencies, like a massive fire.

The Hollywood Reservoir, just minutes from the hustle and bustle of Hollywood Boulevard, is a beautiful spot for hiking and jogging. Like most of the city’s big open-air reservoirs, though, it’s no longer used to store drinking water for the city. That’s because of federal health standards that require the DWP to cover L.A.’s drinking water supply. The DWP is moving forward with a master plan to cover all of its big reservoirs so the water in them isn’t exposed to sunlight. (Photo: Saul Gonzalez)

The remaining open air Los Angeles reservoirs in service will either be covered or decommissioned. In the case of the L.A. Reservoir in Sylmar a facility is being built to treat drinking water with blasts of ultraviolet light to kill contaminants. All of this work at a cost of nearly a $1.5 billion.

On the 100th anniversary of the Los Angeles Aqueduct, we look at William Mulholland’s legacy and the on-going quest to quench LA’s thirst. More at: Power & Water: The Los Angeles Aqueduct at 100 . This series was reported by Madeleine Brand and Saul Gonzalez and produced by Matt Holzman.